I think I play UU enough to give this a rate.
Use White Herb or Normalium Z instead of any other Item on Cloyster. If he has some HP left, he can survive a priority attack or two, which threaten him the most. You could use Normalium Z instead, to get more out of Explosion. Replace Rock Blast with Hydro Pump or Hidden Power Fire. HP Fire is for Scizor, or Hydro Pump for most physically defensive Pokémon. Rock Blast is pretty useless in UU, compared to Hydro Pump. Use a Naughty Nature instead of Adamant, and move the 4 SpD EVs into SpA.
Altaria is a pretty solid Mega. Other than setup sweeping, you'll probably find use it for checking/countering Krookodile or Zeraora, but watch out for Scizor. :P
There are 2 Approaches to Heracross here:
Keep Moxie: Moxie is okay, but Swords Dance is pretty useless when it has Moxie and a Life Orb; the risk of setting up doesn't really justify the reward, especially since Life Orb makes Heracross not want to take as many hits. Replace Swords Dance with Knock Off. Mega Horn is also not great coverage when Close Combat basically covers the same threats; Bullet Seed would help more than Mega Horn. It might be worth using a Choice Scarf instead of a Life Orb, mainly because Moxie Heracross isn't really better than Guts Heracross without boosted Speed. I don't recommend Moxie.
Lose Moxie: Guts+Flame Orb+Swords Dance Heracross reaches a higher attack faster than Moxie Life Orb Heracross with Swords Dance. It takes a minimum of 3 turns for Moxie Hercross to get x4 Attack. Guts Heracross gets x4 Attack in 1 turn, and gets double Base Power on Facade. If you use Guts, give Heracross a Flame Orb, replace Mega Horn with Knock Off, and Replace Rock Slide with Facade.
Chandelure can also be done 2 ways:
Keep Choice Item: Flame Body is useless on Specs Chandelure, especially when it isn't supposed to take many hits. Furthermore, Chandelure has Infiltrator as a better Ability option with Specs. It can also hold it's own against many threats. If you go with Specs, give it Trick instead of Taunt. It is also worth noting that A choice Scarf can help you KO Stuff just as effectively and works better with Trick.
Lose Choice Item: Flame Body with Taunt works, but most Flame Body sets use Leftovers, Calm Mind, Substitute, and 2 damaging moves. It has Flame body because it expects to take hits. If you use a Power Herb on Cloyster, Ghostuim Z is also a viable Item for Chandelure.
"Renegade" is a nickname for Giritina, not your lesser dragon Hydreigon. :P
Hydreigon is Good, but you probably want to steer away from 3 Choice users. This should be fine, since Heracross is better with Guts+Flame Orb anyways.
Empoleon is Good.
Well, that's my take on it.
Hope I Helped!
